Fuel briquette and method of making same



r vantages of the Patented Dec. 31, 1940 UNITED STATES PATENT OFFICE Frank Passarelli, Scranton, Pa.

N 0 Drawing. Application May 3, 1938,

Serial No. 205,838

3 Claims.

This invention relates to a fuel briquette, the product and method of making the same. This application is a continuation-in-part of my application Serial No. 61,807, filed January 31, 1936,

'5 which describes and claims a briquette, themain proportion of the mass of Which comprises anthracite pieces or particles, incorporating two binders, a protein binder functioning during the cold life of the briquette, giving it qualities of coherence which fortify it against disintegration through handling, storage or exposure to weather, and a thermosetting binder which enables the briquette to maintain its integrity to an optimum extent under the action of heat while 15 functioning as a fuel. The protein and thermo setting binders are described in said pending application as having a zone of overlapping function in that in the early heating stage of the briquette, when the protein binder is losing its binding function at the same time that the thermoplastic binder is acquiring its binding function, the heat decomposition which the protein binder undergoes at this time generates gases which have a profound physical effect upon the thermosetting binder, causing it to set porously and thus to increase the combustibility of the briquette.

While the briquette manufactured according to the specification of my aforementioned pending application has been in general satisfactory particularly from the standpoint of its coherence during combustion, it has been found that under certain adverse conditions such as exposure to rainfall, submergence in Water or long storage in damp places is desirable in the strength and water-proof qualities of the protein binder.

It is therefore one of the objects of the present invention to provide a briquette of the general type of that disclosed in said pending application having a protein binder of great strength and resistance to disintegration especially under the adverse conditions above related.

Another object of the invention is to provid a binder for fuel briquettes which has initially on immersion in Water or damp exposure.

Still another object is to provide a method for producing a fuel briquette embodying the adimproved water-proof and strength-retaining binder.

Other objects of the invention will appear as the following description of a preferred and practical embodiment thereof proceeds.

The briquette, subject of the present invention,

consists of a body of anthracite or semi-anthracite coal particles incorporating the protein and thermosetting binding substances. The anthracite particles may be in the form of silt, culm, dust or fines, or they may be ground or crushed especially for the purpose. While the size of the anthracite particles is not critical, they should for optimum performance be able to pass through screens having the following mesh: /16, A 7 these values being expressed as fractions of an inch.

The thermosetting binder comprises bituminous fines which may be in proportion as much as 30 percent of the Weight of the anthracite constituent of the briquette, and should not be less than 5 percent for good results.

The bituminous binder should be of such fineness as to be capable of thorough dispersion throughout the mass of the briquette. The fineness should be such that substantially 60 percent of the bituminous fines will pass through a screen size of at least 50 mesh. In its preferred form, the invention contemplates that a part of the bituminous binder shall be ground together with the protein binder. It is found that the grinding of the bituminous binder with the protein produces a capacity for dispersing in the wetting liquid, soon to be described, in much the same manner in which paint pigments are dispersed in drying oils, distributing the binding material much more thoroughly and uniformly throughout the briquette, mass, resulting in a substantial improvement in the breakage strength and. Water-resistance of the briquette compared with a briquet in which the protein and bituminous binding substance are separately ground and incorporated.

The protein binder may consist of any vegetable substance rich in protein, for example peanut meal or soya bean meal which contains from 38 percent to 41 percent protein. The protein binder should be ground to a fineness at least as fine as that prescribed for the bituminous binder. If the entire amount of bituminous binder or a convenient proportion thereof is ground with the peanut meal or soya bean meal as little as 3 percent of the peanut or soya bean meal on the weight of the entire briquette gives good results.

If the bituminous binder and protein binder are separately ground and separately incorporated in a briquette mass, a somewhat larger proportion of protein is required which may, for example be 6 percent of the weight of the briquette, to

impart equal breakage and water-resistant qualities to the briquette.

A wetting agent is employed to effect the dispersion of the protein binding substance, and where a part of the bituminous binder is ground and mixed with the protein binder, the former shares With the protein binder the advantage of being carried in dispersion in the liquid vehicle to the ultimate voids of the briquette mass.

One of the most important features of the invention is the selection of a wetting agent which after it has performed its function of bringing the binders into intimate contact with the anthracite fuel particles, is capable of being made briquette. Wetting agents which answer this purpose include water-soluble salts of'fatty acids such as the sodium, potassium and ammonium salts and they are preferably used in the form of soaps.

Another important feature of the invention is that the protein is only partially hydrated instead ofbeing entirely hydrated or converted into glue as was the case with the briquette described and claimed in my aforementioned pending application. In this partially converted state, the protein has high strength as a binder and yields a briquette of improved strength and Water resistance.

The soluble fatty acid salt of the wetting agent is rendered insoluble through reaction with calcium hydroxide, and the protein is hydrated to the extent desired through the action of sodium hydroxide. In practice, the sodium hydroxide may be obtained by decomposing part of the calcium hydroxide with sodium carbonate. The amount of sodium carbonate is determined by the desired extent of hydration of the protein, and a sufficient excess of calcium hydroxide is provided to insure enough unconverted calcium hydroxide to react with the soluble fatty acid salt of the wetting agent. If desired, the sodium hydroxide may be directly added to the mixture. A specific example of the manner of making briquettes according to the present invention follows, the percentages being based upon the weight of the fuel constituent of the briquette This fuel constituent may be anthracite 85 percent, in the form of silt, culm, fines, or especially ground or crushed particles; .and bituminous fines 15 percent, this being. the thermosetting binder as well as a fuel constituent. 3 percent of bituminous fines and 3 percent of a vegetable protein-containing substance for example, peanut meal, soya bean meal, linseed meal, are ground together and thoroughly mixed with the anthracite and the rest of the bituminous fines, at a temperature of about 65 C.

A liquid is prepared consisting of about 20 percent water, 2 percent calciumhydroxide, .5 percent sodium carbonate and 5 percent soap (of any soluble fatty acid salt). This liquid is heated to boiling and agitated for a period of from about 5 to 20 minutes. It is then thoroughly mixed with the fuel constituent of the briquette at a temperature of the mass of about 50 C. The immediate function of the liquid when mixed with the fuel is to effect the dispersion of the bituminous and protein binder particles uniformly throughout the mass, this being followed by a change in the character of the wetting liquid and the protein by which change the wetting liquid becomes insoluble under the action of the excess calcium hydrate and the protein becomes partially hydrated under the action of insoluble, thereby water-proofing the the sodium hydroxide,'which changes materially increase the strength and water-proof properties of the briquette.

The moist briquette mass is then pressed and dried, preferably at a temperature of from 70 C. up to 100 C., but it should not exceed the boiling of Water which would create steampressure Within the interstices of the mass that might result in a weakening or disintegration of the mass.

In the above formula, the percentage of calcium hydroxide is in excess of the amount which the stated percentage of sodium carbonate can decompose, leaving part of the calcium hydroxide uncombined with the sodium carbonate. This uncombined excess should preferably be not less than 70 percent of the entire amount of calcium hydrate employed. As has been stated, it is the excess of uncombined calcium hydroxide which combines with the fatty acid salt in the wetting liquid, rendering it insoluble.

The sodium hydroxide resulting from the reaction between the calcium hydroxide and the sodium carbonate will partially hydrate the protein, the proportion of sodium carbonate used being insufficient to completely convert the protein.

The technique of making the briquette may be varied in a number of ways. Instead of incorporating the ground-together mixture of protein and bituminous fines in dry state with the rest of the fuel constituent, said mixture may first be incorporated with the wetting liquid and then added to the fuel mass of the briquette. An alternative procedure is to mix all of the finely ground bituminous binder with the anthracite, and to grind the protein separately and incorporate it with the Wetting liquid before the latter is mixed with the fuel.

It may also be convenient to add the fatty acids, as such, to the wetting liquid and not necessarily in the form of soap, for, in general, saponification results from the reaction of the fatty acid with the other ingredients of the Wetting liquid.

It has been demonstrated by experiment that for good results the amount of calcium hydroxide should be at least 1 percent of the weight of the fuel constituent of the briquette used with a proportion of soap which should be from .15 percent to .5 percent of the weight of the fuel. The calcium hydroxide may of course be sustituted for equivalents such, for example, as ferric hydroxide and zinc hydroxide and the sodium carbonate can be substituted by equivalents such as potassium carbonate. The proportion of the bituminous fines should be from 5 percent to 25 percent of the weight of the fuel content of the briquette. The temperatures employed in the various stages of the process of manufacture are not critical nor is the amount of water employed in the wetting liquid. There should be enough water to moisten the entire mass of the briquette, but the use of more than this is uneconomical in View of the longer time required in drying. The briquettes are formed in molds under a pressure which is of the order-of 150 to 400 pounds per square inch which is in sharp contrast to the enormously high pressures formerly considered necessary. At the low pressures practiced in the present invention, the voids in the mass are preserved, whereas under the excessively high pressures heretofore used, the voids have been closed and the briquette molded into a compact fire-impervious mass.

The behavior of the briquette is as follows: Under conditions of handling the briquette will be found extremely durable, resisting breakage to a remarkable degree, nor will it be subjected to the absorption of moisture or thermal or hygroscopic disintegration under abnormal conditions as where exposed to repeated rainfalls or to submergence in water. When the briquette is first put into the fire, the film of protein binder which lines the surfaces of all the interstices between the particles. is decomposed by the heat, the volatile constituents become gasslfied and find free escape through the pores between the particles. In the initial stage of its heating the briquette is thus preserved from cracking under the pressure of the evolved gases by virtue of the granular structure of the briquette. Incidentally, the consumption of the films of the protein binder enlarge the said interstices and thus improve the porosity of the briquette. As the temperature continues to increase the bituminous particles of the thermosetting binder become plastic and swell in the manner common to bituminous fuel when heated, but the voids between the particles enlarged by being vacated by the protein binder are adequate to receive the swelling particles of the bituminous binder without putting a strain on the briquette as a whole which strain would ordinarily'warp or crack the briquette. During the short time that the bituminous constituent is plastic, the gases resulting from the decomposition of the protein binder are still being evolved so that in escaping they honeycomb the bituminous constituent increasing its porosity and preventing it sealing up and rendering impervious the voids between the particles.

By the time the first binder has lost its function as a binder, the second binder has acquired 40 its binding property by setting under the influence of the increasing temperature so that it is no longer plastic, but forms a porous coke structure in the voids between the anthracite particles and binding them securely together. The

45 porous nature of the briquette at this stage permits access of air to the innermost parts so that it may be completely consumed.

The nature of the coked binder is such that it outlasts the anthracite particles in burning so 50 that it holds them together clear to the surface of the briquette and it is only at the surface that the coked binder consumes into an ash losing its binding properties and permitting the ash of the surface film of anthracite to drop to the grate 55 below assuring at all times a fresh burning surface.

The improvements of the briquette of the present invention over that described and claimed in the hereinbefore mentioned application for pat- 60 ent may be summarized as, first, the employment of a wetting agent in connection with a protein binder with the addition of a compound such as lime that renders the wetting agent insoluble after it has performed its function of bringing the binder into intimate contact with the fuel particles, and therefore water-proofing the briquette. Second, the partial hydration of the protein by which the protein binder is rendered particularly hard, adherent and waterresistant. Third, the grinding of the protein together with at least apart of the bituminous binder until all of the ground mixture passes through a screen at least as small as a 50 mesh, by means of which a colloidal dispersion of the binder particles in the wetting and throughout the mass of the briquette is secured.

It will be understood by those skilled in the art that the specific details of the process of manufacture of the briquette as herein described and the specific ingredients and proportions of the same which constitute the briquette, product of the herein described process, are by way of example, and not to be construed as limiting the scope of the invention as defined in the appended claims.

What I claim is:

1. Process of forming a fuel briquette of base of anthracite fines, comprising grinding solid bituminous fines predominantly smaller than 50 mesh and amounting to 5 to of the anthracite base With protein meal amounting to 3 to 6% of the briquette to serve as binders, admixing the binders with anthracite fines constituting at least 10% of the briquette at a temperature of about 65 C., and intermixing therewith at about 50 C. an aqueous mixture containing a small amount of water soluble soap as dispersing agent, and calcium hydroxide and sodium carbonate, the calcium hydroxide being sufficient to convert the soluble soap into calcium soap and the sodium carbonate into sodium hydroxide, the sodium hydroxide being in quantity insufi'icient for complete conversion to glue of the protein binder, and briquetting the mixture by pressure.

2. Process of forming a fuel briquette of base of anthracite fines, comprising grinding solid bituminous fines predominantly smaller than 50 mesh and amounting to 5 to 25% of the anthracite base with protein meal amounting to 3 to 6% of the briquette to serve as binders, admixing the binders with anthracite fines constituting at least 70% of the briquette at a temperature of about 65 C., intermixing therewith 5 to 25% of water containing water soluble soap up to about 0.5% and calcium hydroxide up to about 1% and sodium hydroxide in quantity insufficient for complete conversion to glue of the protein binder, and briquetting the mixture at pressures of the order of 150 to 400 pounds per square inch.

3. A fuel briquette of anthracite fines base constituting '70 to 95% of the briquette, and a thermosetting binder of bituminous fines of 5 to 25% of the anthracite fines, and having intermixed therewith a low temperature binder of protein meal only partially converted to glue constituting about 3 to 6% of the anthracite fines base, and as dispersing and water-proofing agent calcium soap constituting about 0.15% to 0.5% of the fuel.

FRANK PASSARELLI. 

